The present invention relates generally to the crimping of a moving multi-layer paper web at a plurality of locations along its length by a plurality of blades. More particuarly, the invention relates to a crimp blade holder mounting the blades and a cooperating anvil that are specifically adapted to insure that the various layers of the web remain in proper registration during crimping. Such devices are particularly useful in machines for collating several paper webs, such as might be done in the manufacture of business forms.
Multi-layer, preprinted business forms are commonly used, for instance, where it is desired to make multiple copies of a document at the same time. In manufacturing such forms, a single layer web is printed for each layer of the form, and the individual webs are then supplied to a collator for proper arrangement into layers. Normally, after collating, a perforation is provided across the webs at a plurality of predetermined locations, so that individual forms may be separated from the web for use. The individual forms typically are not separated until immediately before or after use, and the forms are packaged for shipment and/or storage by folding the web in accordion-like fashion along the perforations.
The separation between consecutive perforations along the web is, of course, determined by the desired length for the form. In the United States, the two most common lengths for forms are 81/2" (21.6 cm) and 11" (27.9 cm), and in Europe, the most common lengths are 8" (20.3 cm) and 12" (30.5 cm).
In addition to the perforations provided across the multi-layer web, the web is further provided with a series of holes along each of its edges. These holes may be used for advancing the web, both during manufacture of the forms, and during their use, for instance, where the individual forms are prepared using a computer-driven printer. Typically, the holes are disposed along the edge of the web at a spacing of 0.50 inch (1.27 cm) center-to-center, and equipment used with forms has been designed to be compatible with such spacing.
In order to keep the various layers of the form together until such time as it is desired to separate them, it is common to provide a pluality of crimps along each edge of the multi-layer web during collating. The crimping is normally performed by a series of crimp blades, each of which has a plurality of fingers for cooperating with grooves provided in an anvil surface. The fingers puncture and pass through the web into the grooves of the anvil surface, thereby providing a plurality of slots through the layers of the web. The crimp blades are designed, however, such that the small portions of the paper layers orginally located where the slots are formed are not severed from the web, but rather are pushed downwardly through the slot formed in the underlying layers. These small portions of paper thus serve to hold the various layers together.
The crimp blades are usually mounted to one or more blade holders, an example of which is disclosed in U.S. Pat. No. 2,935,002, issued May 3, 1960 to Robinson, which in turn are mounted to a rotatable shaft. The multi-layer web is passed between the blade holders and the cooperating anvil surface, and the blade holder shaft is rotated at a speed such that the fingers of the crimp blades and the web approach each other at the same linear speed. Thus, as the web is passed by the blade holders, the blades crimp the web in a pattern predetermined by the arrangement of the blades along the holders.
To be effective, the crimps must be located along the web so as to avoid the holes. Accordingly, as can be seen in FIG. 1, the crimps are typically centered 0.25 inch (0.635 cm) from the centers of adjacent holes, and are therefore separated from other crimps by an integer number of half-inches.
The perforations separating successive forms represent yet another constraint on the location of the crimps. The perforations must be located so as not to fall on the holes, and thus, as seen in FIG. 1, are also located 0.25 inch (0.635 cm) from the centers of adjacent holes. It is not desirable, however, for the crimps to fall along a perforation. In such a case, the crimps could cause premature, partial separation of individual forms along the perforation, thereby making accidental full separation much more likely. Moreover, the crimps prevent even, neat folding along the perforations, interfering with the proper arrangement of the web for storage and/or shipping.
In a typical forms collating machine, such as that shown in U.S. Pat. No. 2,859,035, issued Nov. 4, 1958 to Franzmann, or U.S. Pat. No. 3,727,908, issued Apr. 17, 1973 to Whitesell et al, the various individual web layers are assembled along one or a series of pin conveyors, each of which provides an endless belt having a plurality of pins thereon for engaging the holes along the edges of the layers. These pins serve the dual function of moving the web through the collating machine and placing and maintaining each of the individual layers in proper registration as it is added to the multi-layer web moving therethrough. This latter function is important, since over the web path length along the length of the conveyor, which may be in the order of 10 feet (3.05 m), the cumulative tolerance in any one layer of the spacing between the holes may be as great as .+-.3/32 inch (0.238 cm).
The pin conveyor releases the web prior to its passage between the blade holders and anvils for crimping. Following the application of crimps to the web, a second pin conveyor engages the crimped web for further movement through the collator machine. In order to permit engaging of the pins with the holes in the assembled web, it is necessary for a clear hole of at least 0.125" (0.318 cm) to be maintained through the various web layers, and thus it is important for the web layers to be in proper registration.
Despite the noted cumulative tolerance between the holes of each layer, the pins of the conveyor maintain the various layers in registration. This may then result in a small amount of "bubble" between individual layers, but the distribution of such bubble over the length of the web results in it being insignificant insofar as subsequent use of the finished forms is concerned. Nonetheless, it can be seen that the bubble represents an unstable condition with respect to web registration, although the bubbled condition is maintained by engagement of the pins with the holes along the web.
Once the pins release a portion of the web for passage thereof between the crimp blade holders and anvils, the maintenance of that particular portion of the web in registration is discontinued. Thus, any forced bubbling that was introduced for proper registration can dissipate, resulting in movement of one or more of the web layers out of registration. Moreover, even in the case of relatively stable bubbling, passage of the web between the blade holders and anvils will cause flattening of the bubble, thereby further moving the web layers out of registration. This latter problem is present even when bubbling of the web results from causes other than variations in hole spacing. Further, of course, once crimps are applied to the web, any misregistered layers will be secured in such a position, thereby preventing the layers from being reregistered.
What is needed, therefore, is a means by which the various layers of a multi-layer moving web may be held in registration within a collator machine following assembly of the layers up to and through such time as crimps are applied to the web. Such a means would enable the web to be crimped while insuring sufficient clearance through the corresponding holes of each layer to permit subsequent movement of the web, both within the collator and in machines for later use of the forms, by engaging the holes with driven pins. Such a means should be relatively simple in design and operation and, importantly, should be capable of being retrofit onto existing machines without the need for modification or reconstruction thereof.